Evidence for collapsin-1 functioning in the control of neural crest migration in both trunk and hindbrain regions

Collapsin-1 belongs to the Semaphorin family of molecules, several members of which have been implicated in the coordination of axon growth and guidan ce, Collapsin-1 can function as a selective chemorepellent for sensory neur ons, however, its early expression within the somites and the cranial neura l tube (Shepherd, I., Luo, Y,, Raper, J, A. and Chang, S, (1996) Dev, Biol, 173, 185-199) suggest that it might contribute to the control of additiona l developmental processes in the chick. We now report a detailed study on t he expression of collapsin-1 as well as on the distribution of collapsin-1- binding sites in regions where neural crest cell migration occurs. collapsi n-1 expression is detected in regions bordering neural crest migration path ways in both the trunk and hindbrain regions and a receptor for collapsin-1 , neuropilin-1, is expressed by migrating crest cells derived from both reg ions. When added to crest cells in vitro, a collapsin-1-Fc chimeric protein induces morphological changes similar to those seen in neuronal growth con es. In order to test the function of collapsin-1 on the migration of neural crest cells, an in vitro assay was used in which collapsin-1-Fc was immobi lised in alternating stripes consisting of collapsin-Fc/fibronectin versus fibronectin alone. Explanted neural crest cells derived from both trunk and hindbrain regions avoided the collapsin-Fc-containing substratum. These re sults suggest that collapsin-1 signalling can contribute to the patterning of neural crest cell migration in the developing chick.